by Reza Tajali, P.E.

Data center power systems may be high resistance grounded or solidly grounded. In either case, in order to comply with stringent requirements for power availability and quality, multiple power sources are tied together through various arrangements of circuit breakers with automatic transfer schemes. The use of solid grounding creates multiple return paths for fault currents, which makes the design of the ground fault system rather complex. However, no industry standard exists to guide the consulting engineers and users who ultimately specify these systems.